5-Hydroxymethylcytosine (5hmC) is an important mammalian DNA epigenetic modification that has been linked to gene regulation and cancer pathogenesis. Here we explored the diagnostic potential of 5hmC in circulating cell-free DNA (cfDNA) using a sensitive chemical labeling-based low-input shotgun sequencing approach. We sequenced cell-free 5hmC from 49 patients of seven different cancer types and found distinct features that could be used to predict cancer types and stages with high accuracy. Specifically, we discovered that lung cancer leads to a progressive global loss of 5hmC in cfDNA, whereas hepatocellular carcinoma and pancreatic cancer lead to disease-specific changes in the cell-free hydroxymethylome. Our proof-of-principle results suggest that cell-free 5hmC signatures may potentially be used not only to identify cancer types but also to track tumor stage in some cancers.

Immune cells contribute to determining the prognosis of gastric cancer. However, their exact role is less clear.We determined the prognostic significance of different immune cells in intratumoral tissue (T), stromal tissue (S), and adjacent normal tissue (N) of 166 gastric cancer cases and their interactions, including CD3+, CD4+, CD8+, CD57+, CD68+, CD66b+, and Foxp3+ cells, and established an effective prognostic nomogram based on the immune reactions.We found high densities of TCD3+, TCD4+, TCD8+, SCD3+, SCD4+, SCD57+, SCD66b+, and NFoxp3+ cells, as well as high TCD8+/SCD8+ ratio, TCD68+/SCD68+ ratio, TCD3+/TFoxp3+ ratio, TCD4+/TFoxp3+ ratio, TCD8+/TFoxp3+ ratio, SCD3+/SFoxp3+ ratio, and SCD4+/SCD8+ ratio were associated with better survival, whereas high densities of TCD66b+, TFoxp3+, SFoxp3+ and NCD66b+ cells as well as high TCD57+/SCD57+ ratio, TCD66b+/SCD66b+ ratio, SCD8+/SFoxp3+ ratio, and TFoxp3+/NFoxp3+ ratio were associated with significantly worse outcome. Multivariate analysis indicated that tumor size, longitudinal tumor location, N stage, TCD68+/SCD68+ ratio, TCD8+/TFoxp3+ ratio, density of TFoxp3+ cells, and TCD66b+/SCD66b+ ratio were independent prognostic factors, which were all selected into the nomogram. The calibration curve for likelihood of survival demonstrated favorable consistency between predictive value of the nomogram and actual observation. The C-index (0.83, 95% CI: 0.78 to 0.87) of our nomogram for predicting prognosis was significantly higher than that of TNM staging system (0.70).Collectively, high TCD68+/SCD68+ ratio and TCD8+/TFoxp3+ ratio were associated with improved overall survival, whereas high density of TFoxp3+ cells and TCD66b+/SCD66b+ ratio demonstrated poor overall survival, which are promising independent predictors for overall survival in gastric cancer.

Recent evidences show that nervous system acts as a crucial part of cancer microenvironment. Infiltration of nerve fibers into cancer microenvironment has an important active role in cancer progression. The stimulations of both cancer growth and metastasis by members of nervous system such as neurons and glial cells have been demonstrated. However, how the nervous system is built in cancer is largely unknown. Here we show that a fraction of cancer stem cells (CSCs) derived from patients with gastric carcinoma and colorectal carcinoma are capable of producing neurons that are involved in tumor neurogenesis and tumor growth. Cancer stem cell monoclone derived from a single cancer stem cell was able to generate neurons including sympathetic and parasympathetic neurons to take part in the nervous system in cancer tissues. Knocking down the neural cell generating capability of the human CSCs inhibited the growth of xenograft tumors in mouse model. Our data demonstrate that human CSCs are able to produce one of most important components in the cancer microenvironment that are required for cancer development and progression.

Nutritional and immune status is important to the prognosis of patients with gastric carcinoma (GC). Here, we evaluated the prognostic significance of the combination of preoperative hemoglobin, albumin, lymphocyte and platelet (HALP) in patients with GC. From January 2005 to December 2011, 1332 patients with GC who underwent gastrectomy were randomly divided into the training (n = 888) and the validation sets (n = 444) by X-tile according to the sample size ratio 2:1. The cut-point of HALP was 56.8 and the patients were subsequently subdivided into HALP < 56.8 and HALP ≥ 56.8 groups in both two sets. Multivariate analysis revealed that gender (p < 0.001, p < 0.001), tumor size (p = 0.003, p = 0.035) and T stage (p < 0.001, p = 0.044) were independently related to HALP both in the training and the validation sets. Kaplan-Meier (p < 0.001, p = 0.003) and Cox regression (p = 0.043, p = 0.042) showed that the prognosis of HALP ≥ 56.8 group was significantly better than that of HALP < 56.8 group both in two sets (p < 0.001, p < 0.001). Nomograms of these two sets based on HALP was more accurate in prognostic prediction than TNM stage alone. Our findings suggested that HALP was closely associated with clinicopathological features and was an independent prognostic factor in GC patients. Nomogram based on HALP could accurately predict the prognosis of GC patients.

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